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Background. Based on the "green agenda" in the production of cement, reducing the share of clinker in it with the replacement of active mineral additives is relevant. Purpose. Determining the suitability of inorganic raw materials of Karakalpakstan as cement additives and developing practical recommendations for their use.. Methodology. Chemical and mineralogical compositions of raw materials were studied by chemical, optical, X-ray phase, DTA, IR methods. Their compliance with ƠzDSt 901-98 to mineral additives in cement is established in accordance with GOST 25094, pozzolanic activity - in accordance with GOST 25592-2019. Originality. The chemical, mineralogical compositions, hydraulic and pozzolanic activity of the sandstone of the Khodjakul deposit and the Karatau-1 porphyrite have been established. Their quality indicators meet the requirements for additives to cements of the PC400-D20 brand. Findings. The sandstone of the Khodjakul deposit is characterized by high hydraulic and pozzolanic activity. The amount of CaO absorbed from the lime for 30 days is 30.03 mg/l, according to the saturation of the liquid phase with lime 6.84%, the total alkalinity of the solution is 53.6 mekv/l. In the composition of porphyrite, the content of silicon oxide is less than that of sandstone, oxides are higher. It has activity t\u003d 24.47> 2.07, the amount of CaO absorbed from the lime mortar is 24.78 mg / l, according to the saturation of the liquid phase with lime - 6.9%, the total alkalinity of the solution with samples of cement with porphyrite - 56 mekv / l. [ABSTRACT FROM AUTHOR]

The relevance of the study is caused by the need to prevent the introduction of a volume of rock with greater homogeneity and larger size into the near-filter zone compared to the coarse fraction of formation sand – an attempt to improve the filtration properties of the near-filter zone, i. e. decrease in ζ2фк and ζ2n. The design of the gravel pack should simultaneously exclude the removal of formation particles into the well. The solution to this problem will improve the work of filtration of formation fluid from the formation into the well and reduce the cost of additional application of methods for stimulating the inflow of formation fluid to the well. Purpose: to develop a methodology that allows, when choosing a filter design, simultaneously with the ability to provide them with a reliable hydraulic connection in the reservoir-filter system, preventing sand removal into the well. Objects. To prevent the flow of sand from the formation and retain gravel at the bottom of the well, when creating gravel packs, slot, wire, ring, titanium, cermet and other filters are used. These screens, installed in the casing perforation interval without the formation of gravel outer annular packing (and this is how screens are installed in most wells in Russian fields), are very often clogged with formation sand, which leads to a decrease in well productivity. If slot filters are used to retain sand, then the effectiveness of their application depends on the correspondence of the slot size to the granulometric composition of the sand being removed. Filters with shell packing are more effective, but they also do not always meet the set goal, since the strength and quality of shell rock pumped into the near-wellbore part of the formation are rather low. In addition, wire filters used in the fields do not have fixation of each turn, as a result of which, if one of the turns is mechanically damaged, the entire winding breaks down. Methods. When applying the proposed technique, the results of experimental work on evaluating ways to reduce sand production from unconsolidated heterogeneous formations show that the use of filters in a cased hole requires the creation of gravel packing in the annular gap between the filter and the string, in the perforated channel and behind the casing. Moreover, the size of the gravel should be chosen so as to exclude the mixing of the gravel packing with the formation sand due to the migration and intrusion of sand, i.e. D/d=4–5. A decrease in well productivity can in this case be avoided by increasing the size and number of perforations. It should be noted that sand avoidance means that under optimal steady state well operation, the filter retains formation backbone particles, but allows fines and clay particles to pass through. During the well start-up, the picture is somewhat different - part of the skeletal particles is also passed through until a natural filter of sorted coarse fractions is formed on the filtering casing. Results. The particles that make up the rock structure should not be carried out of the formation by applying a filter. In practice, this means that the filter should not pass 75–85 % (by weight) of the larger sand fractions. To maintain the overall stability of the formation skeleton, it is possible to allow the removal of small particles not more than 15–25 % (in weight).

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The relevance of the research is caused by the need to expand the Russian Federation resource potential due to increase in the number of hydrocarbon deposits. Today, oil is a mineral resource, which achieved production levels are not adequately provided with developed field’s reserves. The productive reservoirs structure detailed study within the Vankor fields group in the future will provide an opportunity for forecasting and discovering new hydrocarbon deposits within the Lower Cretaceous Siberian deposits. The main aim of the research is to determine the productive sandstone formation conditions according to the core material study, to study the field structure heterogeneity causes and to identify their characteristic signs for the subsequent forecast of the Lower Cretaceous oil deposits in the area of the Krasnoyarsk region. Objects: oil-bearing sandstone layers in the Yakovlevskaya suite, Lodochnoe oil and gas deposit. Methods: thin sections petrographic analysis, grain size analysis, facies and formation analysis, filtration-capacitive properties core study. Results. The Upper and Lower Yakovlevskaya subsuites sandstones material composition was studied by petrographic analysis, their comparative characteristics are given. The post-sedimentation processes influence on the studied sedimentary rock appearance formation is determined. A facies model that most closely describes the productive layers sedimentation conditions is proposed. The influence of facies sedimentation conditions and post-sedimentary rocks transformations on the sandstones filtration-capacitive characteristics is established. The reasons for the carbonated interlayers presence in fluvial deposits are explained. Conclusions are drawn about the possibility of predicting the Lower Cretaceous sediments productivity accumulated in various facies environments, using the Yakovlevskaya suite in Lodochnoe deposit as an example.

The A. N. Stavrogin's experimental data are observed during triaxial compression of sandstone samples under proportional loading according to T. Karman's scheme. Sandstones have a sufficiently high porosity in the initial state, so their deformation within elasticity has the following peculiar properties. When the cylindrical sample is uniaxially compressed at small initial stresses (of the order of 0.05÷0.15 of the elastic limit), a nonlinear part is observed on the longitudinal strain diagram, which is associated with the material densification occurring on this section. This circumstance causes a certain difficulty in determining the modulus of elasticity. An elaboration of the method for determination the elastic constants (Young's modulus and Poisson's ratio) are proposed taking into account the initial deformation diagram's special feature, which was mentioned. Earlier A. N. Stavrogin proposed to consider on the longitudinal strain diagram a linear part from the indicated initial stress to the conditional elastic limit. The elastic modulus is determined by this part of the diagram. Linear extrapolation of this segment to zero stress level provides a virtually new point of origin for the longitudinal strain under consideration. In this paper, it is shown that under triaxial compression of a cylindrical specimen, the longitudinal strain (satisfying Hooke's law) can be measured from the same new point of origin, which is established under uniaxial compression. In this case, the lateral strain of the sample is considered in the such range of stress variation, at which the increment of the axial stress causes a negative increment in the lateral strain. Based on the initial experimental values of longitudinal and lateral strain, which were adjusted by this method, the conditional elastic limit was determined.

The A. N. Stavrogin's experimental data are observed during triaxial compression of sandstone samples under proportional loading according to T. Karman's scheme. Sandstones have a sufficiently high porosity in the initial state, so their deformation within elasticity has the following peculiar properties. When the cylindrical sample is uniaxially compressed at small initial stresses (of the order of 0.05÷0.15 of the elastic limit), a nonlinear part is observed on the longitudinal strain diagram, which is associated with the material densification occurring on this section. This circumstance causes a certain difficulty in determining the modulus of elasticity. An elaboration of the method for determination the elastic constants (Young's modulus and Poisson's ratio) are proposed taking into account the initial deformation diagram's special feature, which was mentioned. Earlier A. N. Stavrogin proposed to consider on the longitudinal strain diagram a linear part from the indicated initial stress to the conditional elastic limit. The elastic modulus is determined by this part of the diagram. Linear extrapolation of this segment to zero stress level provides a virtually new point of origin for the longitudinal strain under consideration. In this paper, it is shown that under triaxial compression of a cylindrical specimen, the longitudinal strain (satisfying Hooke's law) can be measured from the same new point of origin, which is established under uniaxial compression. In this case, the lateral strain of the sample is considered in the such range of stress variation, at which the increment of the axial stress causes a negative increment in the lateral strain. Based on the initial experimental values of longitudinal and lateral strain, which were adjusted by this method, the conditional elastic limit was determined.

A sedimentational model of terrigenous reservoir rocks is based on the results of structural-paleogeomorphological and lithological-facies investigations. The reconstruction of the paleolrelif in time of the deposition of sandstones is carried out on the basis of the analysis of small thicknesses of one-aged deposits enclosing these sandstones. Minimum values of deposits thickness will correspond to the paleorelief rasing, and maximum ones – to its lowering. The information on the facies composition of rocks was obtained according to the result of studies of their composition, structure, texture, plant and fauna remnants, mineral inclusions, contacts and transitions between layers, interaction with hydrochloric acid and other diagnostic indications. It was also taken into consideration that sand material, which is carried over by linear sedimentary flows with one-directed dynamics of the water surroundings (rivers, their deltas, sewering and marine currents), is accumulated in the lover forms of the relief. Feedback is characteristic of lithofacies of litorial formations: beaches, bars and spits (wave dynamics of water surroundings). As an example we have constructed a sedimentational model of the Upper Serpukhovian productive horizon C-4 that contains the information on the distribution of alluvial, deltaic, avandeltaic, beach sandstones, their contents in the section of the productive horizon. On the basis of the sedimentation model and data of geophysical studies of wells, the regional map of reservoir rocks of the productive horizon C-4 was compilled which contains data on the sandstones thickness and their collecting properties.

The paper represents the results of implementation of liquid and supercritical fluid extraction processes in order to extract oil-products from oil sludge. A mixture consisting of propane (75 wt%) and butane (25 wt%) has been applied as the extractant. Initial oil sludge is characterized by the absence of water and content of solids in an amount of 12.05% by weight. The extraction processes have been conducted in a temperature range of85-160°C and pressure range of 5-50 MPa.

The Upper Triassic sandstones of gas-oil reservoirs of Euphrates Graben in Syria are characterized by certain mineralogical characteristics, conditioned by the processes of sedimentogenesis and diagenesis. In the course of the analytical work, it was possible to establish the nature of minerals composing sandstones and their impact on the porosity of rocks. So, for example, a good sorting of detrital grains and their substantial quartz composition is an important factor determining the increased values of porosity. On the other hand, the increased content of clay and authigenic minerals (more than 10-15%) reduces the porosity of rocks studied. Methods of optical microscopy, X-ray diffraction, electron microscopy and chemical analysis were used when describing sandstone. It is shown that the studied sandstones are quartz. Clay minerals, authigenic quartz and carbonates with a small fraction of amorphous material serve as cementitious material of detrital grains. Studies with a scanning electron microscope in conjunction with dispersive X-ray spectroscopy have shown that quartz is clastic and amounts to an average of 70%, and up to 10% of authigenic quartz is also present in the samples. The same studies show differences in the morphology of quartz, which are found in all samples.

The accelerated development of horizontal drilling technology in combination with the multistage hydraulic fracturing of the reservoir has expanded the geological conditions for commercial oil production from tight reservoirs in North America. Geological and physical characteristics of tight reservoirs in North America are presented, as well as a comparison of the geological and physical properties of the reservoirs of the Western Canadian Sedimentary Basin and the Volga-Ural oil and gas province, in particular, in the territory of Tatarstan. The similarity of these basins is shown in terms of formation and deposition. New drilling technologies for horizontal wells (HW) and multistage hydraulic fracturing are considered. The drilling in tight reservoirs is carried out exclusively on hydrocarbon-based muds The multi-stage fracturing technology with the use of sliding sleeves, and also slick water – a low-viscous carrier for proppant is the most effective solution for conditions similar to tight reservoirs in the Devonian formation of Tatarstan. Tax incentives which are actively used for the development of HW and multistage fracturing technologies in Canada are described. wells, multistage fracturing

Results of the study of volcaniclastic sandstones of the Uskul’ and Il’tibanovo strata of the Lower Devonian are presented. Sandstones are of feldspathic greywacke and greywacke lithoclastic types after classification V.N. Shvanov. They are composed primarily of fragments of basic and intermediate composition volcanic rocks, crystals of plagioclase and pyroxene. Greywacke of Il’tibanovo section are distinguished by the presence of fragments metamorphic, carbonate rocks. These rocks are different from sandstones of the sections Uskul and Talyshman by the composition and distribution of small elements. Island arc is a source of material for the sandstones. The clastic material was transported by turbidite flows.

The article analyzes the adequacy of compliance on paleogeodynamic nature of Upper Precambrian sedimentary associations - Bashkir meganticlinorium, Kama-Belaya aulacogene and Uchur-Maya region, received by geological methods and by using discriminant diagrams ?. Meynard et al., B.R. Roser and R. Korsch, and S.P. Verma and ?.S. Armstrong-Altrin. It is shown that among them there are notable differences.

Base oil and gas complex, of which the new area exploration in the Eastern region of Ukraine consists of lower (subsurface section Precambrian basement) and upper (Precambrian weathering crust, roofing layers of sedimentary rock) sub. It is not only complex discrete distribution channels for fluids confined to fault zones fractured Precambrian basement, but a number of objective difficulties in his study that complicate the determination and geological mapping of the main parameters of the complex. These complications are defining the boundary between the crust and the weathering of sedimentary rock sole, the contact between the upper and lower sub. A sole lower sub is difficult to predict even in theoretical terms. So today the thickness of the base oil and gas complex characterized not only volatility but unfortunately and its uncertainty. Implementation of advanced search technologies in seismic survey (3D techniques, around the hole vertical profiling) and potential fields (methods of electrical and magnetic exploration gravel) and can be a sure foundation for productive mapping sections of the base oil and gas industry. This will be the basis for a new search strategy that is capable of for a long time provide the country with hydrocarbons.

The article tells about the significance of the Jerusalem staircase and the adjoining upper and lower squares in the system of public spaces in Irkutsk. The author proposes reconstruction with the use of not only stone, but also wooden cover for the lower square and the pavement along Podgornaya Street, as well as the active use of local lighting during hours of darkness.

The variations of water permeability of the reservoir rocks with the most productive characteristics for the drinking ground water in the oil regions of Tatarstan are considered. The pore porosity is shown to be responsible for the filter coefficients to 6-10 m /day, whereas the higher values of permeability are determined by fractures porosity. The determining role in the anisotropy of the filtration anisotropy is taken by geomorphological and geological-structural conditions of the territory, and the facial features of the rocks and the depth of their occurrence. On the basis of the established regularities of the behavior of the filtration field, the most probable values of permeability of reservoir rocks for different conditions of their occurrence were calculated.

Purpose. To analyze the influence of structural and morphological, and elastic characteristics of defects on the features of the structure and deformation of some sandstones based on the modeling approach and interpretation of experimental data of velocity of longitudinal and transverse acoustic waves. Methodology. We have involved a series of experimental studies of density, porosity, and determination of the velocity of propagation of longitudinal and transverse acoustic waves in samples of sandstone with different structural organization. Findings. The elastic parameters of defects of solid structure were calculated based on the velocities of propagation of acoustic waves for sandstones with different effective Poisson's ratio. The normal and tangential compliances with the effective Poisson's ratio of sandstone were comparatively analyzed. Poisson's ratio of the medium matrix was calculated based on the variations of the velocities of propagation of acoustic waves under the influence of external pressure. Originality. The deformation behavior of sandstones was considered on the basis of the model of microinhomogeneous medium as an elastic matrix and planar defects inclusions. Theoretical estimates of the parameters of defects, based on the elastic constants of linear elasticity theory, indicate the adequacy of the model to describe the strain state of imperfectly elastic rock. The possibility of the existence of negative Poisson's ratio in sandstones with high normal compressibility and the contribution of the contact interactions were theoretically justified. Practical value. Theoretical estimates of the parameters of defects, based on the elastic constants of linear elasticity theory, indicate the adequacy of the model to describe the strain state of imperfectly elastic rock. There were obtained the relations for evaluation of normal and tangential compliance on the basis of effective elastic moduli microinhomogeneous medium, elastic moduli and the Poisson's ratio of the matrix medium. It is shown that the concentrations of defects in their compliance and effective Poisson's ratio have an inverse relationship, which determines the strain-elastic properties of the medium of propagation of acoustic waves. [ABSTRACT FROM AUTHOR]

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper a new lithostratigraphic scheme of the Upper Cretaceous rocks in the West Srednogorie is proposed. In the present Part 1 seven new formal lithostratigraphic units in the Melove, Lyubash and Sofia tectonic Units are introduced: Paramun, Izvor, Rosoman, Melove, Golesh and Kosharevo Formations, and Kreshna Member of the Izvor Formation. The lowermost Paramun Formation (Lower-Middle Turonian), known as "coal-bearing formation", is a transgessive facies of light-gray to rusty-brown conglomerates, sandstones and siltstones with clay, marl and coal interbeds. It is up to 150-200 m thick and crops out as a thin strip at the base of the Upper Cretaceous sections in all of the West Srednogorie tectonic units. The overlying Izvor Formation (Middle Turonian-Coniacian) in Lyubash and Melove Units consists of more than 230 m strong marls, limestone beds and carbonate concretions with 90 m soft marls in the upper part of the unit north of Lyalintsi village, defined as Kreshna Member. The Golesh Formation (Coniacian-Lower Santonian) is a lateral analogue of the Izvor and Melove Formations, composed of about 180 m weakly cemented sandstones and soft clayey-sandy marls between Izvor and Melove Formations in Melove Unit. The Melove Formation (Coniacian-Santonian) is composed of up to 250 m thinbedded carbonate turbidites cropping out in Melove, Lyubash and Sofia Units. The Rossoman Formation (Santonian-Lower Campanian) is composed of more than 750 m alternating volcanic-sedimentary rocks with argillite-marl-limestone interbeds widespread in Sofia Unit. The Kosharevo Formation (Lower Campanian) is composed of more than 92 m marls, limestones, sandstones and polygenetic conglomerates. [ABSTRACT FROM AUTHOR]

The Precolnitsa graben (West Bulgaria) spreads out over entire Kamenitsa cattle and continues on the territories of Serbia (to the North) and Macedonia (to the West). Paleogene terrigenous sedimentary and volcano-sedimentary successions in association with syn- and postsedimentary acid volcanic bodies of the linear Ruen magmato-tectonic zone crop out in the graben. The stratified successions form the large NW-SE (135-140°) fault bounded Devebair asymmetric graben-syncline. The same is the trend of the strips both of the intragraben horsts and of the cutting volcanic bodies. The units in all of the lithostratigraphic models of the Precolnitsa graben paleogene filling are described as Formations and Members, consisting of both bedded and unbedded lithologies but according to the requirements of the Stratigraphic Code they have to be considered as "nomen nudum" only. This discrepancy together with some new data called for an actualization of the lithostratigraphic division. The following changes were made in the most frequently used model (Fig. 3, columns 2, 3, 5): a) taking into account the lateral variations of the stratified successions and their interruptions by cutting volcanic bodies and steep faults, the formal lithological units are recategorised into informal ones - formations and packets; b) the breccia-conglomerate formation (20-400 m) is regarded an equivalent of the Tsarven dol Formation of the previous model; c) the bedded volcanogenic rock varieties of the Gueshevo Formation from the lowermost levels of the Percolnitsa section are united with the pyroclastic Tsreshnevo Formation in a volcaniclastic formation (about 100 m?), which is interfingered with the basal breccia-conglomerate formation; d) the volume of the Dolno selo Formation is divided into two packets. The first packet is variegated and consists of sandstones and small pebble conglomerates with lenses of limestons and fine white tuffs (up to 120 m). The second packets (>600-700 m) is a siltstone-conglomerate-sandstone one; e) the volcano- sedimentary formation (200-400 m?) consists of bedded rocks, related to the growth and partly - to the erosion of the Gyueshevo paleovolcano (pyro- and epyclastics, rare sheet-like lava bodies) and of synchronous sedimentary deposits; f) The Jedilovo Formation is united with the second member (B62) of the Velbajd Formation (ИBaHOB et al., 1971) in a sandstone-conglomerate formation; g) the lithostratigraphic units are characterized using the data, available up to the end of 2012. The age interval of the Precolnitsa stratified rocks deposition is still under discussion: a) according to the determinations of spore-pollen assemblages and macrophauna nearly all the section, including the upper levels of the volcano-sedimentary formation, belongs to the Upper Eocene (Priabonian); b) according to some radiogeochronologic determinations of pyroclastics and epyclasts the Paleogene sedimentation starts on the territories of Eastern Serbia and near-border part of Bulgaria by the end of the Late Eocene (at about 35-34 Ma) ± synchronously with the earliest events of the subaerial exsplosive acid volcanism. It continues in Latest Priabonian and Earliest Oligocene (together with synsedimantary volcanic activity at the Gyueshevo locality: 33-31.6 Ma) being interrupted by the Devebair assymetric graben-syncline formation and the following intrusion of the polistage postsedimentary Kopriva subvolcanic stock (32-30 Ma). In the frame of such a possible scenario the Eocene-Oligocene boundary coincides with the early events of the synsedimentary volcanism at the Gyueshevo locality. [ABSTRACT FROM AUTHOR]

The soils formed on sandstones in sessile oak forests (Quercetum montanum typicum Čer. et Jov. 1953) were researched in the area of Fruška Gora. On permanent sample plots established in management units "Čortanovačka Forest-Hopovo-Velika Remeta" and "Beocin-Manastir-Katanske Livade-Osovlje", in the are of NP "Fruška Gora", aiming at the monitoring of the effect of light regime on the development of sessile oak progeny in the given environmental conditions, based on the morphogenetic characteristics of the soil and analytic values of the soil properties, and based on the soil classification by Škorić et al. (1985), the following two soil types were defined: acid brown soil (dystric cambisol), and illimerised soil (luvisol). Acid brown soil belongs to the form of medium deep soils, and illimerised soil is classified as deep soil. [ABSTRACT FROM AUTHOR]